1. Field of the Invention
The present invention relates to a network processor and a host system which operate together to capture packets on a link of a high-speed packet network and detect respective packet media streams from the captured packets in accordance with a trigger.
2. Description of the Related Art
Communications are often transmitted over a high-speed, packet network. For example, a communication might be a voice over Internet Protocol (VOIP) telephone call comprised of signaling packets and corresponding Internet Protocol (IP) packet media streams. The signaling packets include information indicating, for example, when the VOIP telephone call is initiated, when the VOIP telephone call ends, what parties are participating in the VOIP telephone call, etc. The signaling packets would typically be based on a signaling protocol such as, for example, SIP. SIP is a well-known protocol used for signaling packets of a VOIP telephone call. However, many other signaling protocols are available.
The packet media streams (often referred to as “flows”) are formed of media packets which carry data. If the communication is a VOIP telephone call, the media packets would typically be real-time protocol (RTP) packets. RTP is a well-known protocol used for media packets of a VOIP telephone call.
FIG. 1 is a diagram illustrating the use of a call signaling analyzer to monitor a VOIP telephone call. Referring now to FIG. 1, a call signaling analyzer 4 is directly connected to a network link 6 of a network under test. Call signal analyzer 4 can detect the signaling packets (i.e., the SIP packets) for a respective VOIP telephone call transmitted over network link 6.
However, call signaling analyzer 4 cannot detect the packet media streams (i.e., the RTP packets). Therefore, with call signaling analyzer 4 in FIG. 1, only information conveyed by the signaling packets can be monitored. For example, from the signaling packets, it can only be determined when the VOIP telephone call is initiated, when the VOIP telephone call ends, what parties are participating in the VOIP telephone call, etc.
Moreover, it would often be desirable to detect specific packet media streams in accordance with a trigger (i.e., a specification, such as the occurrence of a specific event, for triggering capture of respective media streams). Call signaling analyzer 4 in FIG. 1 cannot detect specific packet media streams in accordance with a trigger.